3. 回滚
回滚之前
mysql> select * from user; +----+------+----------+ | id | name | password | +----+------+----------+ | 1 | rain | 12345 | +----+------+----------+ 1 row in set (0.00 sec)
执行代码
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String
from sqlalchemy.orm import sessionmaker
# 创建连接
engine = create_engine("mysql+pymysql://root:root@127.0.0.1/cmz", encoding='utf-8', echo=False)
Base = declarative_base() # 生成ORM基类
# 创建表结构
class User(Base):
__tablename__ = 'user' # 表名
id = Column(Integer, primary_key=True)
name = Column(String(32))
password = Column(String(64))
# 直接调用基类下的方法
Base.metadata.create_all(engine)
# 实例与socket绑定,创建与数据库的绘画session class，注意，这里返回
# 给session的是一个class，不是实例
Session_class = sessionmaker(bind=engine)
# 生成session实例，cursor
Session = Session_class()
# 创建用户
fake_user = User(name='leco', password="666666")
Session.add(fake_user)
# 回滚
Session.rollback()
Session.commit()
mysql> select * from user; +----+------+----------+ | id | name | password | +----+------+----------+ | 1 | rain | 12345 | +----+------+----------+ 1 row in set (0.00 sec)
删除Session.rollback() 执行后结果
mysql> select * from user; +----+------+----------+ | id | name | password | +----+------+----------+ | 1 | rain | 12345 | | 2 | leco | 666666 | +----+------+----------+ 2 rows in set (0.00 sec)